From the director of "Old School" comes a new comedy about a bachelor party gone horribly wrong.

Two days before his wedding, Doug (Justin Bartha) and his three buddies (Bradley Cooper, Ed Helms and Zach Galifianakis) drive to Vegas for a blow-out night they’ll never forget. But when the three groomsmen wake up the next morning with pounding headaches, they can’t remember a thing. Their posh hotel suite is beyond trashed and the groom is nowhere to be found.

With no clue of what happened and little time to spare, the trio must attempt to retrace their bad decisions from the night before in order to figure out where things went wrong and hopefully to get Doug back to L.A. in time for his wedding.